The present invention relates to an apparatus for measuring an optical characteristic of a liquid specimen in order to determine a purity thereof, to identify and to determine a concentration of a solute contained therein, and particularly relates to a polarimeter applicable to an urinalysis apparatus. More specifically, the present invention relates to an apparatus and a method for transfusing a liquid specimen into a sample cell for the measurement.
In general, optical characteristics, for instance, absorbance and optical activity, of a specimen are derived by projecting a light onto the specimen accommodated in a sample cell and analyzing a light transmitted through the specimens. As the sample cell, a box-shaped container mainly made of glass having a pair of transparent light-transmitting windows is used.
The measurement on such optical characteristics has conventionally been conducted by introducing the specimen into the sample cell through the open top end thereof by using a squirt, a pipette, a syringe or the like, and installing the sample cell in an optical system. In this procedure, for introduction or exhaustion of the specimen, and for washing the sample cell, there is required a detachment of the sample cell from the optical system. As shown, the measurement on the optical characteristics was poor in operability and required much man power. In addition, if bubbles exist in an optical path of the sample cell, the obtained measurement values are liable to show uneven values.
Recently, an urinalysis using a polarimeter is proposed, for instance, in International Patent Publication No. WO97/18470. Glucose or a protein i.e., albumin demonstrates an optical activity. It is therefore possible to derive concentrations of these substance in a urine by conducting a polarimetry on the urine. In the conventional urinalysis, a test paper impregnated with a reagent was dipped into the urine and the color reaction thereof was observed by spectrophotometer or the like. On the contrary, it is possible to detect and to determine glucose and protein in a low concentration without requiring any expendable supplies such as test papers as required in the conventional urinalysis, according to this method.